A. Technical Field
The present invention relates to micro rate of rotation sensors for detecting a plurality of rates of rotation about orthogonal axes x, y, and z.
B. Background of the Invention
A generic micro rate of rotation sensor using MEMS technology is known from U.S. Pat. No. 6,308,567 B1, wherein driving masses are driven to oscillate. When a rate of rotation about one of the three orthogonal X, Y, or Z-axes occurs, masses are deflected out of the drive plane or rotated about the Z-axis. Sensor elements are associated with the masses in order to be able to detect the deflections. The deflections occur on the basis of Coriolis forces acting on the masses in case of a corresponding rotary motion and displacing the masses in the corresponding direction. In the embodiment example shown in said publication, the masses are driven toward a center and are rotated about an X-axis, a Y-axis, or a Z-axis due to the Coriolis forces. Sensor elements associated with said masses detect the corresponding rotary motion by means of electrical signals that occur by changing the spacing of fixed electrodes and displaceable electrodes. The signal change provides information about the rate of rotation that acted on the sensor.
A disadvantage of said embodiment is that such a sensor is very sensitive to external force effects, which can cause false measurements. The sensor shown also requires a large area on the substrate. The sensor is also sensitive to temperature, because deformation of the individual elements due to temperature effects can slightly falsify the results.